1722218 - https://codepen.io/shubniggurath/pen/oNZLQJW lags

Status: RESOLVED WONTFIX

(Core :: JavaScript Engine: JIT, defect, P3)

Description

[Mayank Bansal]

https://codepen.io/shubniggurath/pen/oNZLQJW lags a lot. It is slow in Chrome too, whuch probably implies its a poorly written demo

I am filing this bug only to see if there is anything obvious we can improve. If nothing is low-hanging or easy, I will be happy to WONTFIX.

https://share.firefox.dev/3x5iTFp

Comment 1

[Iain Ireland [:iain]]

It looks like 1/3 of the total time is spent in the following function;

function e(t2, a2) {
  if (!Object.prototype.hasOwnProperty.call(t2, a2))
    throw new TypeError("attempted to use private field on non-instance");
  return t2;
}

It looks like a polyfill for private fields. I expect it would be faster if the demo used the native private fields implementation (available in Firefox 90).

Comment 2

[Nicolas B. Pierron [:nbp]]

Iain, do you think we should investigate this issue, or close this bug?

Comment 3

[Iain Ireland [:iain]]

Given that it's also slow in Chrome, and there's an obvious way to fix the demo, I think it's fine to close this.